Some snail shells coil clockwise and some coil anti-clockwise. True or False and why?

"Lose yourself in Nature and find Peace!"(Ralph Waldo Emerson)UNITE AGAINST POACHING...What we protect, do not let poachers take it away!Extinction is forever and survival is up to---every last one of us!

TRUE. Different snail species seem to have different spiralling coils, although within a population most show similar coiling. The reason comes down to mating as opposite coils cannot get their genitalia together. Also, predators who have developed more teeth on one side of their mouth (such as certain snakes), are more successful killing snails with one type of coil as opposed to the other.

In theory, snails can come in two enantiomorphs: either dextral (coiling clockwise) or sinistral (coiling counter-clockwise). In snail species where both forms are actually present, coiling direction is determined by a single gene with delayed maternal inheritance; there is no predictable relationship between a snail's own coiling genotype and its actual coiling direction. Because of this genetic decoupling, it might be expected that dextral and sinistral individuals would be exact mirror images of one another. However, indications exist that there is a subtle but detectable shape difference between dextral and sinistral individuals that derive from the same gene pool.

"Lose yourself in Nature and find Peace!"(Ralph Waldo Emerson)UNITE AGAINST POACHING...What we protect, do not let poachers take it away!Extinction is forever and survival is up to---every last one of us!

Reproduction : breeding snails are put in cages at a density of 200 Petit-Gris or 100 Gros-Gris per m² (i.e. about 4 lb. per square meter), with food and water ad lib., and some pots which are filled with a good soil. Ideally, these boxes are placed in a room which is kept at 20° Celsius (68° F), with a relative humidity of 95%, and a long photoperiod (16L / 8D). But we can also simply use a greenhouse. Snails are hermaphrodites but they have to mate before laying some days later.

When a snail has laid, the pot is placed into an incubator at 20° C and covered. Three weeks later, about 100 new hatched snails appear under the lid.

Usually, we can expect a yield of 70 young snails per breeder for 2 months.

Nursery : cages with well moistened soil are stocked with less than 2500 young snails per m², in the same "climatic conditions" than breeders. 3 to 4 weeks later, these young snails are brought outdoor.

Outdoor pens : I advise to stock them with no more than 300 Petit-Gris or 150 Gros-Gris per square meter, in order to have a really good growing. We have to protect them against rodents and shrews, for example with a grid in the ground. With a mosquito net as lid we both protect snails against birds and prevent escaping